lam1 = 1529;  
de1 = [0.808, 0.807, 0.813, 0.812, 0.814, 0.809];  
c = 4200;  
x =sin(pi/4)* [0.6, 1.2, 1.8, 2.4, 3.0, 3.6];  
kap1 = c * de1 / lam1;  
y = kap1;  
xc = [0.3, 0.4, 0.5, 0.6,0.7];  
yc = spline(x, y, xc,); 
disp(yc);
